Implemented more formalised CAS chunk filtering (with plenty of room for optimization)

1 files changed, 39 insertions, 0 deletions

diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index 04a6f7aa0..cddf22503 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -279,6 +279,45 @@ FileCasStrategy::FindChunk(const IoHash& ChunkHash)
 	return Chunk;
 }
 
+bool
+FileCasStrategy::HaveChunk(const IoHash& ChunkHash)
+{
+	size_t							 Shard2len = 0;
+	ExtendableWideStringBuilder<128> ShardedPath;
+	ShardedPath.Append(m_Config.RootDirectory.c_str());
+	ShardedPath.Append(std::filesystem::path::preferred_separator);
+	MakeShardedPath(ShardedPath, ChunkHash, /* out */ Shard2len);
+
+	RwLock::SharedLockScope _(LockForHash(ChunkHash));
+
+	std::error_code Ec;
+	if (std::filesystem::exists(ShardedPath.c_str(), Ec))
+	{
+		return true;
+	}
+
+	return false;
+}
+
+void 
+FileCasStrategy::FilterChunks(CasChunkSet& InOutChunks)
+{
+	std::unordered_set<IoHash> HaveSet;
+
+	for (const IoHash& Hash : InOutChunks.GetChunkSet())
+	{
+		if (HaveChunk(Hash))
+		{
+			HaveSet.insert(Hash);
+		}
+	}
+
+	for (const IoHash& Hash : HaveSet)
+	{
+		InOutChunks.RemoveIfPresent(Hash);
+	}
+}
+
 void
 FileCasStrategy::Flush()
 {